Vortex Generators are fitted on both sides of the base of the Fin, on Tornado Aircraft, to generate a turbulence, so that the Rudder has an effect at altitude, otherwise the Rudder is flying in a vacuum, and has no effect on the stability of the aircraft, causing judder, with possible buckling of the spine to occur.
It is a technology that takes time to be built. Older aircraft are very difficult to modify due to safety rules and insane cost levels. These two things make sure not every airplane looks the same.
Tail
It depends on what you classify as 'cannons' . Many aircraft were fitted with 20mm guns in exactly the same way as machine guns were. Some aircraft such as the Stuka, some other German aircraft and a few British aircraft were fitted with larger guns of 37- 40-mm calibre and these were often carried in pods under the wings and had very limited ammunition due to it's weight.
Delta has more Wi-fi equipped aircraft than anyone else as of Oct 2013. Not all aircrfact are fitted at the moment. This is especially the case with regional aircraft such as the CRJ200. Also, Wi-Fi does not currently work over the ocean but they are switching to a satellite based system so that eventually all aircraft will be fitted with this facility.
This is to disperse static electricity ween the aircraft lands. Many aircraft also have 'static wicks' which are bits of wire fitted to the trailing edge of wings.
Most aircraft are fitted with a gyroscope which is used to maintain orientation while an aircraft is changing direction or climbing and descending.
You need to be specific with this, which aircraft, which variant of the aircraft, right down to which engines are fitted, what load you are carrying etc etc etc Any change to this data will change the service ceiling.
All aircraft are fitted with brakes (much like a car) -however - with large aircraft, the pilot can set the engines to 'reverse thrust' which brings the plane to a stop quickly.
Airbus aircraft are fitted with modern equipment and have a very good reputation for comfort and saftey
It was the Ryan aircraft that Charles Lindbergh fitted out for his solo flight across the Atlantic.
Yes, wall outlets are progressively being fitted to the Delta aircraft fleet.
Aircraft don't always "have" missiles. They are fitted with a mix of missiles or bombs according to each mission. The Tigershark was a fairly small aircraft, close to the ground and had limited hardpoints (where missiles are fitted) It could carry 2 Sidewinders and 2 of either Sparrow or Maverick, but 4 missiles was the limit.